Plug-and-play bots run on unique programs called "profiles" which are script coded and set in stone. They do not learn from opponents or have artificial intelligence like Deep Stack or the "bots that beat the pros" do. What the current online
poker bots do is determined by pot/card/position/stack sizes. Their advantage is never tiring, multitabling, and not going on tilt. Their job is to just break even vs players - their profit comes from rakeback (mostly) and clearing bonuses.
Some of the newer bot profiles can read opponents based on PT4 stats but that's only useful really in headsup and after some
hands. Botters mostly use PT4 stats just to avoid setting their bot at tables with sharks. They use an automation tool called a hopper to do table selection for them.
A lot of bots sit at headsup tables. I would avoid playing these ones. A bot is much stronger in headsup (even the creators of Deep Stack said it would not do as well in 6-9). I lost $50 trying beat one at 25NL once. Sometimes the owner will take control of it when you shove thinking you will take advantage of the bot's script to force a fold to a
bluff. Then you get a surprise. Many times they are letting their bot run on a side monitor on a virtual machine and they step in on big pots or when they get premium hands. Otherwise they just let it run auto-pilot, and half the time might just be AFK entirely.
(speaking for just Hold'em)
about 90% of bots play NL1-25
about 9% play NL 50
1-% at NL100+